/*-
 * Copyright (c) 2008-2010, Oleg Estekhin
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 *  * Redistributions of source code must retain the above copyright notice,
 *    this list of conditions and the following disclaimer.
 *  * Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the distribution.
 *  * Neither the names of the copyright holders nor the names of their
 *    contributors may be used to endorse or promote products derived
 *    from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE FOR
 * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
 * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH
 * DAMAGE.
 */

package oe.assertions.predicates;

/**
 * An operator used to combine the results of individual predicates in order to evaluate the result of a composite
 * predicate.
 */
public enum CompositeOperator {

    /** Logical AND operator. */
    ALL_OF() {
        @Override
        public boolean initial() {
            return true;
        }
        @Override
        public boolean combine( boolean a, boolean b ) {
            return a && b;
        }},
    /** Logical OR operator. */
    ANY_OF() {
        @Override
        public boolean initial() {
            return false;
        }
        @Override
        public boolean combine( boolean a, boolean b ) {
            return a || b;
        }};

    /**
     * Returns the initial value.
     *
     * @return the initial value
     */
    public abstract boolean initial();

    /**
     * Applies this operator to the specified values.
     *
     * @param a the first value
     * @param b the second value
     *
     * @return the combined value
     */
    public abstract boolean combine( boolean a, boolean b );

}
